What Are the Causes of Tsunamis?

A tsunami is a type of natural disaster that consists of large waves in a body of water, and it can be the result of any event that creates underwater disturbances. The most common causes of tsunamis are earthquakes on the floor of bodies of water, which account for about 75% of all tsunamis. Landslides, in which land moves down into water and pushes the water away from the land, are thought to be responsible for about 8%, and volcanic activity is estimated to cause around 5% of tsunamis. One of the least common causes of tsunamis is meteorological events, which account for less than 2% of these disasters. About 10% of all tsunamis have an undetermined cause.

More about tsunamis:

• A tsunami's wavelength can be as long as about 125 miles (about 200 km).


• As of early 2014, the most deadly tsunami is thought to have been the 2004 Indian Ocean tsunami, which is estimated to have caused more than 200,000 deaths and was the result of an earthquake in Indonesia.


• Tsunamis can travel as fast as 500 miles per hour (804.67 km/h) and can move across the entire distance of the Pacific Ocean in less than 24 hours.

Frequently Asked Questions

What natural events typically trigger tsunamis?

Tsunamis are most commonly caused by underwater earthquakes, which occur when tectonic plates shift abruptly along faults beneath the ocean floor. This sudden movement displaces large volumes of water, generating waves that can travel across oceans. Other triggers include volcanic eruptions, landslides, and, less frequently, meteorite impacts, which can also displace water and create these powerful waves.

How do underwater earthquakes lead to tsunamis?

When an underwater earthquake occurs, the seafloor may abruptly rise or fall, displacing the water above it and creating waves that radiate outward. These waves can travel at speeds exceeding 500 miles per hour, according to the National Oceanic and Atmospheric Administration (NOAA). As they approach shallow coastal waters, their speed decreases, but their height increases, potentially causing massive waves to crash onto land.

Can volcanic eruptions really cause tsunamis?

Yes, volcanic eruptions can cause tsunamis, particularly if the eruption is explosive or causes a part of the volcano to collapse into the sea, creating a landslide. The Krakatoa eruption in 1883 is a historic example, where the resulting tsunami waves reached heights of over 100 feet and caused widespread destruction, as documented by the Smithsonian Institution's Global Volcanism Program.

Are tsunamis and tidal waves the same phenomenon?

No, tsunamis and tidal waves are not the same. Tidal waves are caused by the gravitational pull of the moon and the sun on the Earth's oceans, leading to predictable high and low tides. Tsunamis, on the other hand, are caused by sudden displacements of large volumes of water due to events like earthquakes or landslides, and are not related to the tides.

What role do landslides play in the formation of tsunamis?

Landslides, both underwater and on the edge of coastlines, can generate tsunamis when massive amounts of debris fall into the water, displacing it and creating waves. These waves can be localized but devastating. For instance, the 1958 Lituya Bay megatsunami in Alaska was caused by a landslide and resulted in the highest wave ever recorded, reaching 1,720 feet, as reported by the United States Geological Survey (USGS).

How often do meteorite impacts cause tsunamis?

Meteorite impacts are a rare cause of tsunamis. The probability of a large meteorite hitting the Earth and causing a significant tsunami is low, but it is not impossible. Historical records and geological evidence suggest that such events have occurred in the distant past, but with much less frequency than tsunamis caused by earthquakes or volcanic activity.